For God's sake.

Cantilever mounts, like the ones pictured in the above post, or any mounts on the barrel, are inherently more accurate than receiver mounted scopes. This is a fact, not an opinion. You may own a gun that shoots great with a receiver mounted scope, but most will not shoot as well as most cantilever set-ups.

Pump shotgun barrels are not rigidly mated to the receiver and they can wander a bit from shot to shot. With a cantilever mount, if the barrel wants to wander, the scope wanders right along with it and accuracy is preserved.